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ABLE 1 -CHECKLIST OF REQUIRED DATA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: Eggiman's Hydraulic, 1112 E. Harding Wy.,Stockton,San Joaquin County(RB#390108) 7711. Distance to production wells for municipal,domestic, A 1999 sensitive receptor survey reported fourteen agriculture, industry and other uses within 2000 feet of the water supply wells(nearest 800'west)within 2,000'of site. the site.None of the wells are threatened by the release. Y 2.Site maps, to scale,of area impacted showing locations of In 4/87, two 1,000-gallon gasoline USTs were removed. any former and existing tank systems, excavation contours and sample locations,boring and monitoring well elevation contours,gradients,and nearby surface waters,buildings, streets,and subsurface utilities; Y 13.Figures depicting lithology(cross Site lithology consists of clay,silt,and sand to 65', the total depth investigated. section), treatments stem diagrams; NI 4.Stockpiled soil remaining on-site The fate of the excavated soil is not discussed in the available reports;possibly or off-site disposal(quantity); returned to the USTs pit. y 5.Monitoring wells remaining on-site, Eleven(11)monitoring(MW-1 through MW-11)and seven(7)remediation wells ate; (OS-1s, OS-2s, OS-1d, OS-2d,and OS-3 through OS-5) will be properly destroyed prior to closure. 6. Tabulated results of all groundwater Depth to groundwater varied from 35'bgs to 53'bgs. Groundwater flow elevations and depths to water; direction varied from north to southeast. Groundwater gradient varied from 0.0002 ft/ft to 0.0039 ft/ft. 7. Tabulated results of all sampling All data adequately tabularized in various reports. and analyses: Y❑ Detection limits for confirmation sampling QY Lead analyses LyJ8. Concentration contours of contaminants found and those remaining in The extent of the identified contamination soil and groundwater,and both on-site and off-site: is described in the available reports. 0 Lateral and Y❑Vertical extent of soil contamination Lateral and F1 Vertical extent of groundwater contamination 9.Zone of influence calculated and assumptions used for subsurface The engineered remediation was USTs remediation system and the zone of capture attained for the soil and removal,ozone injection(0I),and natural groundwater remediation system; I attenuation. 10.Reports/information Unauthorized Release Form ❑Y QMRs(37)11-01 to 11-11 Qy Well and boring logsPAR [y FRP ❑y Other No Further Action Report,3/13 _YJ 11.Best Available Technology(BAT)used or an Oland natural attenuation. explanation for not using BAT; Y 12. Reasons why background was/is Residual soil and groundwater contamination remains. ttainable using BAT; Y1 13.Mass balance calculation of substance Consultant estimated TPH mass as 2,850.55 lbs in soil and 1.96 lbs in treated versus that remaining; groundwater. 7y 14. Assumptions,parameters,calculations Site is a repair shop that passed LTCP and Tier 2 Risk Assessment for and model used in risk assessments,and fate soil to soil vapor. Consultant states site does not represent a significant and transport modeling; risk. Y 15. Rationale why conditions remaining at Soil and groundwater contamination reportedly are limited in extent. site will not adversely impact water quality, Land use(commercial)is not expected to change in the foreseeable health,or other beneficial uses;and future. Consultant estimated time to reach WQGs as 2064. Groundwater lume is stable and declining. By: JLB Comments:In 4/87, two 1,000-gallon gasoline USTs were removed at the subject site.Residual soil and groundwater contamination remains.Based upon the limited extent of contamination reported in soil and Date: groundwater,a stable and declining concentration plume, no foreseeable changes in future land use 5/29/2013 (commercial), and minimal risks from groundwater,soil vapor and soil,Regional Board staff concur with San Joaquin County's Closure Recommendation.